This invention relates to an electromechanical clutch for an engine cooling fan.
Experience has conclusively demonstrated that operation of the engine cooling fan is necessary only during a relatively small percentage of the time that a vehicle engine is operated. If the fan is driven when it is not necessary, the power used to rotate the fan is wasted, thereby increasing gasoline consumption. Accordingly, it is desirable to provide a device which disconnects the fan during certain engine operating conditions. Existing clutches used to control operation of engine cooling fans are torque limiting viscous devices, and are responsive to ambient air temperature at the clutch. However, clutches of this type are relatively heavy, expensive, and inefficient.